The objective is to establish different phenotypic subtypes of NIDDM so that families differing in these key characteristics can be separately studied in subsequent linkage analyses,thus reducing genetic heterogeneity of NIDDM and increase our power to identify genetic markers. Short tandem repeat poly-morphisms will then be systematically assessed at less than 10 cM intervals of genomic DNA,and linkage analyses will be performed using effective sib- pair affective pedigree, and "lod" score analyses.q